Pressure on A&E departments is out of control and unsustainable, the NHS regulator has warned.

David Prior, chairman of the Care Quality Commission (CQC), said there should be widespread closures of hospital beds and investment in community care to tackle the increasing burden on emergency care.

Prior said far too many patients were arriving at hospital as emergency cases, a problem that could be averted by earlier intervention through care in the community.

This has put such pressure on the healthcare system that it is on the brink of collapse, he said – meaning regulators cannot guarantee there will never be another care disaster such as that in Mid Staffordshire, according to the Daily Telegraph.

Speaking at a conference hosted by the health thinktank the King's Fund, Prior said: "If we don't start closing acute beds, the system is going to fall over. Emergency admissions through accident and emergency are out of control in large parts of the country … That is totally unsustainable."

Prior, who was brought in to lead the CQC in January after it faced criticism for failing to protect vulnerable patients, said almost half of hospitals were now providing care which was either poor, or "not terribly" good.

He said the commission had found 45 hospitals with problems dating back five years, and adding that regulators would now take a much clearer approach in advising which ones should not be allowed to continue as they are.

"We will be outside the system and the politics – we will have a huge role in the reconfiguration debate because we are independent," he said.

Prior partly blamed the problem on a lack of a market in healthcare, leaving patients with little choice but their local hospital, regardless of its quality.

"The patient or resident is the weakest voice in the system. It is a classic market failure – the user doesn't know nearly as much as the professionals, even with the internet," he said.

Prior said it was unlikely the CQC could give a "cast-iron guarantee" that it would be able to prevent future healthcare scandals such as Mid Staffs.

He also criticised a decision by the previous government to allow family doctors to opt out of out-of-hours care, saying the decision had let patients down.